Already known from WO 2007/118626 A1 is a tool holder with an expansion sleeve deployed within a main part, the expansion sleeve being formed to receive a tool and capable of being compressed with hydraulic fluid to clamp the tool in place. The tool holder further includes a safety catch that contains multiple corresponding counter elements to engage with the blocking elements deployed in the main part, in order to prevent the axial slippage of the tool during the processing. In this known tool holder, the blocking elements are realized as bolts or balls that can slide into corresponding drilled holes in the main part, and engage with corresponding clamping grooves on the shank of a tool to be clamped. In this tool holder, however, the main part must be handled in a time-consuming way to release the blocking elements.